Retirement Calculator
See what your retirement savings grow into by the age you stop working, and how long the money lasts once you start spending it. Enter your age, what you save each month, and what you plan to withdraw.
Nominal dollars: inflation, taxes and Social Security are not included, and the projection stops at age 100.
Formula and calculation
Worked example
Start at 35 with $50,000, add $500 a month and earn 7% a year, and by 65 the balance reaches $965,339.05 — $230,000.00 of it paid in by you and $735,339.05 of it investment growth. Spend $65,000 a year from there while the rest earns 4%, and the money lasts until age 87.33: a -2.67-year gap against the life expectancy of 90.
What this projection leaves out
Four things a single line on a chart cannot show. Inflation: spending stays flat here, so a 30-year retirement at 2.5% inflation needs about double the nominal spending by the final years. Sequence of returns: the same average return hurts far more when the bad years land early in retirement, and no average-based model captures that. Taxes: withdrawals from a traditional 401k are taxed as ordinary income, so the pot funds less than it looks. And Social Security, which many retirees rely on, is not included — enter your spending net of it.
What the results mean
- Balance at retirement
- What your savings grow to by the age you retire, at the return you entered. This is the pot every later figure draws on.
- Money lasts until age
- The age the money runs out if you withdraw your annual spending and keep earning the retirement return. If it is still funded at 100 the model stops there and says so.
- Surplus or gap
- Years of spending your savings cover against the life expectancy you entered. A positive number is surplus; a negative number is the gap to close.
- Total contributed
- Everything you pay in: your current savings plus every monthly deposit up to retirement age. Compare it with the balance to see how much of the pot is growth.
- Investment growth
- Investment growth by retirement age: the balance minus everything you contributed. Over 30 years this is usually the larger share.
- First-year withdrawal rate
- Your first-year spending as a percentage of the balance at retirement. Rates above roughly 4% raise the odds of running out of money.
- Balance left at age 100
- What is left at age 100, where this model stops. Zero means the money ran out earlier; a positive figure means it outlasts the projection.
Frequently asked questions
How much do I need to retire?
It depends on what you spend. The common shortcut is 25 times your annual spending: $65,000 a year implies about $1.6 million, which is the 4% rule in reverse. Enter your own age, savings and spending above — the age the money runs out is the number that matters, not the target.
What is the 4% rule, and can I still rely on it?
The 4% rule comes from William Bengen's 1994 study of US market history, later repeated by the Trinity study: withdraw 4% in year one, raise it with inflation, and the portfolio survived most 30-year periods. Critics note it was fitted to one country's past, ignores fees and taxes, and assumes a 30-year retirement — many planners now treat 4% as a rough ceiling, with 3 to 3.5% safer for a 40-year horizon.
What return should I assume for a 401k?
Over the last century a diversified US stock portfolio returned roughly 7 to 10% a year before inflation, but that average hides decade-long stretches that were far worse. Many planners model 6 to 8% for the saving years and 4 to 5% after retirement, when the mix shifts toward bonds. Try more than one number: a plan that only works at 9% is not a plan.
Does this include Social Security, inflation or taxes?
No. Every figure is in nominal dollars and spending never rises, so $65,000 in the first year of retirement is still $65,000 thirty years later. In real life inflation pushes spending up and Social Security and taxes move money both ways. A rough fix: subtract 2 to 3% from the return to read spending in today's dollars, and enter spending after whatever Social Security would cover.
Why does my money last past age 100?
Because your withdrawal rate is below the return you entered: at 4% withdrawals against a 4% return the pot barely moves, and below that it keeps growing. This model stops at 100 and reports what is left instead of projecting further. Only a lower return, higher spending or a shorter horizon changes that answer.